I know many people are having this problema, but any of the solutions seems to work. My wifi was working perfectly with 13.04, but when I updated to 13.10 it just seems that my laptop doesn't have a wifi.

As requested by experienced users in other posts, this is the output of lspci

Thank you @Tim. I'll find a wired connection to try the upgrade or to try Mint as suggested by lonesword. Actually, 13.10 is also giving another problem with USB, so I can't even download the packages using Windows and take them to ubuntu. I'll let you know here as soon as I made it.
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Leandro GuedesNov 15 '13 at 18:36

I have a friend with the same problem. However, his problem was fixed when he upgraded to 13.10. He said under the 'drivers' section (search the dashboard) his adapter was listed among proprietary drivers.

Or else you can get cheap wifi adapters. Works like a charm in ubuntu. And better signal strength too.

Or try linux mint. Mint is basically ubuntu + proprietary drivers. So chances are that your wireless adapter will work in mint.